STEVAL-TCS003V1 STMicroelectronics, STEVAL-TCS003V1 Datasheet - Page 55

• Manufacturer Part Number: STEVAL-TCS003V1
• Description: BOARD DEMO EXPANDER STMPE2403
• Manufacturer: STMicroelectronics

Specifications of STEVAL-TCS003V1

• Main Purpose: Interface, GPIO Expander
• Embedded: No
• Utilized Ic / Part: STMPE2403
• Primary Attributes: 8/16/24-Bit 24-Port GPIO Expander over I2C
• Secondary Attributes: 3 8-Bit PWM Output for LEDs, Keyboard Matrix Scan, Special Key Support
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8206

STMPE2403
12.8.4
12.8.5
Priority of Key detection
Dedicated key will always be detected, if it is enabled.
When a Special Function key is detected, the matrix key scanning on the same input line will
be disabled.
Up to 3 matrix keys will be detected. Matrix keys that fall on activated Special Function keys
will not be counted.
As a result of these rules of priority, a matrix key will be ignored by the keypad controller
when the special function key on the same input line is detected, even if the matrix key is
being pressed down before the special function key. Hence, when a matrix is reported “key-
down” and it is being held down while the corresponding special function is being pressed, a
“no-key” status will be reported for the matrix key when the special function key is reported
“key-down”. If the matrix key is released while the special function key is still being held
down, no “key-up” will be reported for the matrix key. On the other hand, if the matrix key is
released after the special function key is reported “key-up”, then a new “key-down” will be
reported for the matrix key, followed by “key-up”.
Keypad Wake-Up from sleep and hibernate modes
The keypad controller is functional in sleep mode as long as it is enabled before entering sleep mode.
It will then wake the system up into operational mode if a valid key press is detected.
In the case of hibernate mode, the ‘Hib_Wk’ bit in ‘KPC_row_msb’ register must be set to ‘1’ in order to
enable system wake-up by valid key press. When this is enabled, asynchronous detection of keypad
column input activity will be turned on during hibernate mode. If any key activity is detected, the
system is expected to enter sleep mode temporarily to allow de-bouncing of key press to take place. If
a valid key is detected, the system will then wake up into operational mode; otherwise, the device will
go back into hibernate mode.
Keypad controller
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